nature and nurture in suburban spaces

The first creature that caught my eye on the first day of 2019and caused me to pick up my camera, was this garden orb spider. Its complex round web was strung across the vertical spikes of a Common Rush (Juncus effusus) next to our garden pond.

Garden orb spiders (Argiope) occur across the world, including in the Americas, Europe, Asia, Australia and Africa. There are many species in this genus, and I was not able to pinpoint which species this very beautiful garden orb spider is.

This female garden orb-weaving spider has banded colours on her legs that sport delicate sensory hairs. The abdomen is beautifully marked. Spiders have multiple eyes rather than the compound eyes of insects and they have no antennae but have obvious palps that are used when feeding, and used during reproduction in males.

This female garden orb spider waits in the centre of her web ready to attend to any prey that may get caught in the web.

In the photo above, the spider is moving away from the centre in response to a disturbance in the web, but in this instance the potential prey flew off without getting caught and the spider returned to the centre of the web where she spends most of her time waiting.

May orb spiders eat the central part of the web at night and rebuild that section of web again each morning.

This wasp did not manage to escape the web. The spider bites prey items and envelopes them in silk to immobilise them, and usually returns later to eat them.

In the above photo the spider is eating a bug that previously she had bitten and wrapped in silk when it got stuck in the web. The venom she injects into a victim immobilises it. Prior to eating, the spider injects digestive fluid that includes enzymes that liquefy the insides of the prey animal, which the spider eats by sucking the liquid into her stomach.

Many spiders that weave circular (orb) webs include zigzags of thick silk known as stabilimenta. Two vertical zigzags can be seen in the web in the above photograph. It is speculated that stabilimenta serve several functions, which might include providing camouflage or distraction from the spider in the centre of the web, serving as a warning to birds not to fly into the web (and break the web), attracting insects to fly into the web as the stabilimenta reflect ultraviolet light, and also making stabilimenta may be a way of depositing surplus silk and/or stimulating the production of more silk.

Most spiders are harmless to people and should, where possible, be left undisturbed. The intricacy and engineering of the webs are worthy of our admiration. Most spiders benefit gardeners by eating many insects and other creatures that gardeners may consider to be pests. In any event, I found this spider to be an elegant and decorative presence in the garden, albeit surprisingly easy to overlook.

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naturebackin

Sharing insights and celebrating the creatures and plants that inhabit and enrich suburban spaces, with images mostly from my own garden in the KwaZulu-Natal Midlands in South Africa and sometimes from further afield.

Spider fan over here! 🙂 What a beautiful creature. Unusual shaped abdomen. I used to see a different species of golden orb-weaver when I was collecting data on jaguars in Mexico and they’re certainly one of those species that add a distinct touch to local biodiversity.

What a way to start off the new year! The webs are utterly amazing. We generally try to escort any spiders visiting in the house, but like having them outside. Their webs can be quite exquisite, though I’ve also seen some sloppy ones. You’ve outdone yourself with these beautiful captures.

I am currently preparing a post on the golden orb-web spiders, Carol, so I read this article of yours with even more interest than usual (if that’s even possible!?). I really do appreciate the effort you put into these and I can’t wait to see what you’ll be featuring every week.

I look forward to your post on the golden orbs.
And thanks, I kind of look forward to what I will be featuring too as what I decide to do is generally a snap (just noticed the pun :)) decision! I enjoy learning more as I prepare each post (though sometimes I do get a bit obsessive about an obscure detail or go off on interesting tangents and have to get back on track) and I really value your comment.

Thanks Anne. We used to find many more golden orb spiders in our area years back and their numbers have definitely declined. The apparent decline in insect numbers generally for whatever reason(s) are likely related. I should think the drought must have made an enormous impact. I do so hope your area has improved prospects for rain soon …

Lovely photos Carol. As you say, they are impossible to identify to species level (i.e. distinguish between A. flavipalpis and A. levii) without examination of the epigynum, so Argiope sp. it must be 🙂

Thank you Paul. And thanks also for the possible shortlist of A. flavipalpis and A. levii – I was not able to get that far. Thanks too for first drawing my attention to the stabilimentum a few posts ago.